import java.util.*;
public class Example2_5 {
    public static void main (String args[]) {
        int start = 0,end,middle;
        int a[] = {12,45,67,89,123,-45,67,20165211};
        int N = a.length;
        for(int i=0;i<N;i++){
            for(int j=i+1;j<N;j++){
                if(a[j]<a[i]){
                    int t=a[j];
                    a[j]=a[i];
                    a[i]=t;
                }
            }
        }
        Scanner scanner = new Scanner(System.in);
        System.out.println("输入整数，程序判断该整数是否在数组中");
        int number = scanner.nextInt();
        int count = 0;
        end = N;
        middle=(start+end)/2;
        while(number!=a[middle]){
            if(number>a[middle])
                start=middle;
            else if(number<a[middle])
                end=middle;
            middle=(start+end)/2;
            count++;
            if(count>N/2)
                break;
        }
        if(count>N/2)
            System.out.printf("%d不在数组中.\n",number);
        else
            System.out.printf("%d在数组中.\n",number);

    }
}
